Electric contactor



c. H. R|PPLI ELECTRIC CONTACTOR Original Filed Oct. 2l, 1958 2Sheets-Sheet l (ttorneg Nov. 4, 1941. C, H, RIPPL 2,261,929

ELECTRIC CONTACTOR Original Filed Oct. 2l, 1938 v 2 Sheets-Sheet 2 ntorPatented Nov. 4, 1941 2,261,929 ELECTRIC CONTACTOR Charles H. Rippl,Cleveland, Ohio, assignor to The Clark Controller Company,

Cleveland,

Ohio, a corporation of Ohio Original application October 21, 1938,Serial No. 236,248. Divided and this application April 26, 1939, SerialNo. 270,147

10 Claims.

This invention relates to electric contactors and particularly toelectric contactors the operations of which are time controlled.

My invention has particular usefulness when employed in association withelectric spot or resistance welding apparatus to time the duration ofthe welding current; to time the cold hold period during which theelectrodes remain engaged with the work after the welding current isinterrupted; to time the frequency oi suocessive welding operations,etc.; and will be described herein as applied to those uses, although itis to be understood that my invention is not limited to these uses.

It is among the objects of this invention, to provide:

An improved electric contactor generally;

An electric contactor having improved means adapted to control theduration of welding current at the electrodes of a welding machine, andthe time during which the electrodes remain engaged with the work afterthe welding current is interrupted, and the frequency of successivewelding operations, singly or jointly;

An electric contacter arranged to control one electric circuit for atime period and then initiate the running of another time period tocontrol another electric circuit, in an improv-ed manner.

Other objects will be apparent to those skilled in the art to which myinvention appertains.

My invention is fully disclosed in the following description taken inconnection with the accompanying drawings in which Fig, 1 is adiagrammatic view illustrating an embodiment of my invention;

Fig. 2 is a fragmentary view similar to a part of Fig. 1, showing amodification;

Figs. 1A and 2A are views illustrating, to an enlarged scale and inlongitudinal section, parts illustrated in elevation in Figs. l and 2respectively.

This application is `divisional from my copending application SerialNumber 236,248, iiled October 2l, 1938, for improvements in Electricwelding control apparatus, in which subject mat ter illustrated anddescribed herein. but not claimed is being claimed.

Referring to the drawings, Fig. l, I have shown at I, a welding machinecomprising upper and lower heads 2v and 3, spaced apart; a stationaryelectrode 4 associated with the lower head 3; and a movable electrode 5associated with the upper head 2.

The electrode 5 is connected to Y a piston 6 in a cylinder 1 andnormally held in its upper position by a spring 8 in the cylinder andarranged to be moved downwardly, to pressure-engage work 9 between theelectrodes, by fluid pressure, such as compressed air, in the cylinderabove the piston. At I6 is a source of fluid pressure, such ascompressed air, and the diagrammatically illustrated source I0 may beconsidered as comprising a reservoir of compressed air and any means formaintaining air therein under pressure.

At Il is illustrated generally an electro-magnetic valve having anenergizing winding I2 and an actuating plunger I3.

At I4 is illustrated generally an electro-magnetic relay.

Illustrated generally at l5 is an electric welding current controllingcontactor and associated parts which will now be described, and thisdescription will be followed by a more complete description of thewelding machine I, valve Il and relay I4 in connection with adescription of the entire system.

A supporting panel IS has mounted thereon a fram-e I1 comprisinglaterally extending brackets I8 and I9. A plunger 20 reoiprocates at itsupper end portion in a bore 2| in the bracket I9, and at its lower endwhich is of reduced diameter as at 22, reciprocates in a bore 23 in thelower bracket I8, the reduction of diameter providing a shoulder 24 onthe plunger normally resting on the bracket I8 and providing a downwardstop for the reciprocating plunger.

On one side of the plunger is mounted a cam 25, having an inclined camsurface 25. A contactor operator arm 21 is mounted on a shaft 2Boscillatable in a bearing 29 supported on the bracket I8 and in abearing 30 supported in any suitable manner. On the upper end of the arm21 is a finger 3| pivoted to the arm 21 at 32, constrained to rockclockwise on the pivot 32 by a spring 33 and stopped in that directionby a stop 34 on the arm 21. A roller 35 on the other side of the pivot32 is disposed adjacent to the cam face 26.

.Fill

When the plunger 20 is reciprocated upwardly in a manner to bedescribed, the cam race 2E engages the roller 35 and inasmuch as thefinger 3l cannot rotate in the clockwise direction the upwardly movingcam rocks the arm 21 clockwise, the roller 35 rolling down the inclinedcam face 26. As the plunger moves upwardly, the roller 35 ultimatelyrolls off the cam and a spring 35 abutting at one end upon the arm 21and at the other end on the frame I1, then rocks the arm 21counterclockwise to its original position, which position is determinedby a stop 31 on the arm 21 engaging the panel I6.

When the plunger 29 is reciprocated downwardly in a manner to bedescribed, the cam 25 engages the roller 35 and rocks the nger 3| on thepivot 32 against compression of the spring 33, allowing the cam 25 topass beyond the roller 35 without moving the arm 21, and at the end ofthe stroke of the plunger 20, the roller 35 snaps back to itsillustrated position by action of the spring 33.

By this means on each reciprocation upwardly of the plunger 26 the arm21 will first be rocked clockwise and then counterclockwise and willremain inert when the plunger 20 descends.

On the shaft 28 is mounted a pair of contactor arms 38-38 carryingcontacts 39-39. When the arm 21 is rocked as described, it rocks theshaft 28 which rocks the arms 38-38 to move the contacts 39-39 intoengagement with stationary contacts 40-40 rendered yieldable by springs4I-4I.

When the shaft 38 is rocked in the other direction by return of the arm21, the contacts disengage.

By this means upon each upward reciprocation of the plunger 20, thecontacts 39 and 4D are engaged for a time interval depending upon thevelocity of movement of the plunger 20 and upon return movement of theplunger 20 the contacts remain disengaged.

The contacts 39 and 40, which thus are closed for a time period, close awelding circuit to the electrodes of the welding machine I, as follows.Current flows from a supply main 42 by a wire 43 to one of the contacts4D and thence through the corresponding contact 39 and arm 38 to theprimary 44 of an electric transformer and thence by the other arm 38 andthe other contacts 39 and 40 and by a wire 45 to the other supply main46.

The two terminals of the secondary 41 of the transformer are connectedby wires 48 and 49 respectively to the electrodes 4 and 5 of the machineI, and the electrodes being at the time engaged with the work 9, as willbe described, the said timed current ows through the work 9 and makes aweld thereat.

To reciprocate the plunger 20 as described the following means isprovided.

A spring 50 abuts at its upper end upon an arm on the frame I1, and atits lower end abuts upon a bar 52 which is on the upper end of theplunger 20 and thus the spring reacts upon the plunger normally tendingto reciprocate it downwardly.

A valve housing shown generally at 53 and illustrated more in detail inFig. 1A, is mounted on the bracket I8, preferably by means of screwthreads 54 on the housing threaded into corresponding threads on thebracket I8. The housing 53 has formed therein a cylinder 55 axiallyaligned with the reduced diameter portion 22 of the plunger. the latterhaving thereon a piston 56 in the cylinder 55 the reduced diameterportion 22 thus functioning as a piston rod.

Fluid pressure is admitted to the cylinder 55 under the piston 56 toreciprocate it and the plunger 20 upwardly, the fluid pressure beingunder control of valve means within the housing 53 which will now bedescribed in connection with Fig. lA.

In the housing 53 is a duct 51 the lower end of which has connectedthereto a fluid pressure conduit 58 to be referred to. At the upper Cilend of the duct 51 is a cross duct 59 communicating with a downwardlyextending duct 60 which opens into a valve cylinder 6l in whichreciprocates a trunk piston type valve 62. A spring 63 within the valveabuts at its upper end upon the closed upper end of the valve and at itslower end abuts upon a tubular screw 64, threaded in a thimble 65 whichin turn is threaded in the end of the valve cylinder 6I. The tubularscrew 64 may be adjusted by turning it to adjust the tension'of thespring 63 and may be locked in adjusting position by a lock nut 66.

The upper end of the valve 62 is of reduced diameter, as at 61, andunder pressure of the spring 63 closes the open end of the duct 60against fluid pressure therein except at pressures above a predeterminedvalue, at which pressure the fluid pressure moves the valve 62downwardly against the tension of the spring 63.

The wall of the valve cylinder 6I has formed therein axially spacedannular passages 68 and 69. The annular passage 68 communicates by aduct 10 with a bore 1I which communicates by a duct 12 with the maincylinder 55 below the piston 56. A needle valve 13 is threaded into thebore 1I and the tapered upper end thereof projects into the duct 12 toadjust the effective size thereof.

An exhaust duct 14 also communicates with the cylinder below the piston56 at one end of the duct and at the other end opens into a bore 15. Aball check valve 16 normally closes the lower end of the duct 14 and isheld in sealing closing engagement therewith by a spring 11 abutting atits upper end upon the ball 16 and at its lower end upon an adjustingscrew 16. A duct 19 communicates with the said annular passage 68 andwith the bore 15 and a duct 80 communicates with the annular passage 69and the bore 15. One or more ports 8I-8I are provided in the skirt ofthe valve 62 normally opening into the annular passageway 69.

In the operation of the device as thus far described, when the fluidpressure in the conduit 58,

which is a rising pressure as will subsequently appear, attains apredetermined value determined by adjustment of the spring 63, thispressure in the duct will move the valve 62 downwardly. The moment theupper end 61 of the valve uncovers the duct 60, the full upper area ofthe valve is exposed to the pressure and its continued downward movementis quick and positive, and the valve moves downwardly uncovering theannular passageway 68. Thereupon air from the duct 60 flows through theduct 19 and holds the ball valve 16 firmly in sealing engagement withthe end of the duct 14. The fluid under pressure also iiows through theduct 10, and passing the needle valve 13, flows into the duct 12 andinto the cylinder 55 and moves the piston 56 upwardly causing theplunger 2U to reciprocate upwardly as described.

The rate of upward movement of the piston 56 will be determined by theadjustment of the needle valve 13 and thereby the time duration of thecurrent impulse at the contacts 39 and 40 will be adjustably determinedthereby as will now be clear.

When fluid pressure is discontinued in the conduit 58 as will bedescribed later, the spring 63 will return the valve 62 upwardly andagain close the duct 60, and in this position of the valve it exhauststhe fluid from the cylinder 55 downwardly through the duct 14 liftingthe ball check valve I6 and into the bore 15, thence by yduct 80, toannular passageway 69, through the said ports 8|-8l in the wall of thevalve 62, into the interior of the valve and downwardly outwardlythrough the tubular screw 64.

The piston 56 and plunger 20 therefore are now returned downwardly bythe said spring 50.

To avoid operation of the valve 62 by fluid pressure in the duct 90which might leak around the end 51 of the valve and expose the valve toan operating pressure force before the pressure in the duct 0 hasattained the said predetermined value, the space around the reduceddiameter end 61 of the valve is at all times eX- hausted by a bleederduct 82 communicating with the atmosphere at a port 83.

As will be understood, the threaded lower ends of the needle Valve 13and the screw 18 seal the lower ends of their corresponding bores 1| andand they may be adjusted and locked in any adjusted position by locknuts 84 and 85.

Referring again to Fig. 1, when the plunger reciprocates upwardly thebar 52 on the upward end of the plunger and moving therewith engages anadjustable stop 85, preferably in the form of two lock nuts on thethreaded stem 81 of a piston valve 88 reciprocating in a bore 89 in ablock 90 mounted on the frame I'I, moving the valve upwardly from itsnormal position illusn trated. When the plunger 20 reciprocatesdownwardly, the arm 52 engages a spring 9| abutting at its upper end onthe lower side of the arm 52 and at the lower end upon the upper end ofthe valve 88 to restore it downwardly, a head 92 on the Valve engagingthe upper side of the block 90 to stop and position it in its downwarddirection.

The valve 88 has a neck 93 of reduced diameter which, when the Valve israised to its upper position, effects communication between a duct 94and an exhaust duct 95. The upper position of the valve 88 may bestopped and determined by a head 9S on the lower end of the Valveengageable with the lower side of the block 90 when the Valve movesupwardly, to align the neck 93 with the ducts 94 and 95.

Mounted upon the arm 5I of the frame is a cylinder 91 in whichreciprocates a piston 98 having a stem 99 projecting downwardly out ofthe cylinder. A spring |09 surrounding the stem externally of thecylinder abuts at its upper end upon the cylinder end and at its lowerend on a collar |8|` en the stem, thus tending to move the piston 98downwardly. The piston is normally held upwardly by a spring |02reacting on one end of a pivoted lever |03, the other end of whichengages the underside of the collar IDI. When the lever |03 is rocked ina manner to be described to release the stem 99, the spring |00 movesthe piston 98 downwardly and its rate of movement is adjustably retardedby a needle valve screw |04 which controls the rate at which atmosphericair iiows through a port |05, past the needle valve screw |04 and intothe cylinder above the piston S8 through a port |05.

When the piston 98 is raised by the spring |02 acting through the lever|03, air may be eX- hausted from the cylinder above the piston through aball check valve |07, which, when the piston 98 descends, closes.

The lever |03 is rocked as described by the end of an adjustable screw|88 on the bar 52 when the plunger 20 moves upwardly.

When the piston 98 and stem 99 move downwardly, the stem, at the end ofthe time interval determined by the retarded movement of the piston 98,engages one end of a pivoted auxiliary contact arm |09 and rocks itagainst the tension of a spring IIO to move the other end away from acontact III.

The bar 52 also has an adjusting screw ||2 which, when the plunger 20 isin its lower position engages one end of a pivoted auxiliary contact arm|I3, and rocks it against the tension of a spring ||4 to engage theother end with a contact II5. When the plunger 20 moves upwardly thespring ||4 rocks the arm ||3 to disengage the contact |I5.

The description of other parts of the system of Fig. 1 not hithertogiven will now be given in connection with a description of theoperation of the apparatus as a whole which follows.

To effect a weld at the work 9, a normally open operators controlcontactor IIt` is closed by the operator. Thereupon current flows fromthe supply main 42 through the contactor IE5 and through engaged contact|I5 and pivoted arm IIS, by a wire to the winding ||8 of the relay I4and through the winding to the other supply main 455.

The relay I4 is thereby operated and closes contacts at H9. Thereuponcurrent flows from the line 42 through a maintaining circuit comprisinga wire |20, the auxiliary contact arm |09, engaged Contact III, a wire|2I, the closed contacts at ||9 and the winding ||8 to the main 46,whereby the operators contactor IIS after momentary closure thereof maybe released.

When the relay I I4 was operated, it also closed contacts at |22 andthereupon current flowed from the supply main 42 by a wire |23 throughthe winding I2 of the magnetic valve and back through the contacts at|22 to the other main 45, causing the plunger I3 of the valve to belifted. The plunger I3 moves a valve plunger |24 from the lower positionshown in which the plunger is held downwardly by a spring |25, to anupper position at which a duct |20 in the plunger effects communicationbetween ducts |21 and |28 in the valve structure.

Fluid pressure thereupon ows from the source I0 by a conduit |29 throughthe now aligned ducts, |2'I, |25 and |28 to a conduit |30 and to thecylinder l' above the piston 6. The fluid pressure moves the pistondownwardly and en gages the work 9 between the electrodes 5 and 4.

Fluid pressure in the cylinder 'I builds up toward the pressure valve ofthe source and thus iirrnly engages the electrodes with the work.

The above described conduit 5% also communicates with the cylinder abovethe piston 6 by a conduit 58A and the rising pressure in the cylinder iscommunicated to these conduits. Referring to Fig. 1A, the spring t3 isadjusted so that the rising pressure in the conduit 5S will not attainsuflicient value to move the valve E2 downwardly until after thepressure in the cyl inder l has risen suiliciently to fully engage theelectrodes with the work with the desired pressure thereat.

When, however, the pressure in the conduit 58 has risen suiiiciently,the valve B2 is moved downwardly, and, as described above, iluidpressure is admitted to the cylinder under the piston 55 and the plunger2li is thereby reciprocated up-r wardly closing and then opening againthe contacts 35i-49, thereby sending a welding current of timed durationthrough the electrodes 4 and 5 and performing the weld at the work.

The upward movement of the plunger 20 also moves the adjustable screw|08 into engagement with the pivoted lever |03 and rocks it against thetension of its spring |02 relieving the outer end of the lever from thecollar on the stem 99 of the piston 98. The spring |00 then starts thepiston 98 downwardly at a retarded rate of movement determined by theadjustment of the needle valve |94. During its time interval, theelectrodes 4 and 5 are still pressure-engaged with the work 9, althoughthe welding current has been interrupted and this time period may becalled a cold-hold period. At the end of this time period, the stem 99of the piston has moved downwardly far enough to engage the free end ofthe pivoted lever |09 and rocks it disengaging its other end fromcontact and breaking the above described holding or maintaining circuitfor the winding ||8 of the relay |4, which relay then moves to restoredcondition, breaking both its maintaining circuit and the circuit to thewinding |2 of the magnetic valve I The spring |25 of the valve thereuponrestores the valve plunger |24 downwardly which aligns the duct |26 ofthe valve plunger with the ducts |3| and |32, cutting off the fluidpressure from the cylinder 'I and connecting the cylinder to atmosphereto exhaust it, and allowing the spring 8 to restore the electrode 5.

When the plunger 20 was reciprocated upwardly as above described tostart the cold hold time interval at the piston 98, it also, byengagement of the bar 52 with the stop 86 on the valve stem 8T raisedthe valve 88 to its upper position thereby connecting the conduit 58 toatmosphere by way of the duct 94, the neck 93 of the valve and the duct95. The pressure above the valve 62 in the housing 53 is thereuponrendered insufficient to hold the valve down against the spring 63 sincethe conduit 58 is open at its upper end to atmosphere, at the duct 95.Therefore the valve 82 moves upwardly to the position illustrated inFig. 1A, thereby opening an exhaust from under the piston 56, past theball check valve 16 through the duct 80 to chamber 69 through the portor ports 8| in the skirt of the valve, to the interior of the valve, andthence downwardly through the tubular screw 64 to atmosphere. Theplunger 20 is now moved downwardly by the spring U aided by gravity, andrestores the valve 88 to its down or illustrated position. The escape ofair from the cylinder 55 through the path just described, continueshowever, independently of the valve 88 once the valve 62 is restored,and is controlled by the screw "i8, the upper end of which overlaps moreor less the entrance to the duct 80 so that the downward rate ofmovement of the plunger is adjustably retarded.

When the plunger 20 reaches its down position and restores the valve 88the parts areagainready for another operation.

By the means above described it will therefore be observed that thecold-hold period is adjusted by the screw |94 and the frequency or delayperiod is controlled by the screw 'I8 each independently of the other.

In the above described structure as shown in the drawings, it will beunderstood that the conduit 58A extending from the cylinder 'I to theconduit 58 may be a relatively long conduit whereas the conduit 53 fromthe valve block 90 to the valve housing 53 is relatively short inpractice. In any case, the exhaust effected by the valve 88 whilesufficient to exhaust the cylinder 55 through the adjustment provided bythe screw 18, is insufficient to exhaust the cylinder 1, the exhaust ofthe latter being controlled by the valve While the duration of thewelding current mpulse is determined substantially solely by theadjustment of the needle valve 73 for long current impulses during whichthe roller 35 remains in contact with the cam surface 26 during theupward movement of the plunger 20, for short current impulses theplunger 20, whose velocity is adjusted by the needle valve '|3 may be sorapid that the roller will be given an impulse of movement which willcause the arm 2l to rock suiiiciently rapidly that the roller 35 willleave the cam surface. A weight |33 is provided on the arm 21 below itspivot axis and such short impulses will be timed by the spring 36tending to return the arm to open the contacts and by the kineticinertia of the weight |33 tending to keep them closed. This feature andothers of the current timing parts of the contacts above describedconstitute the subject matter of the patent of Edward G. Beiderman, No.2,196,488, April 9, 1940, for improvements in Time controlled electricswitches, to which reference may be had for a complete description.

The structure, functions and arrangement of the parts in the housing 53constitute the subject matter of the patent of Charles H. Rippl, No.2,172,261, September 5, 1939, for improvements in Pressure controls forpneumatically operated switches, and reference may be had thereto.

During long current impulses when the needle valve 13 permits the air toiiow at a slow rate to the cylinder 55, pressure under the piston in thecylinder might otherwise have a tendency to leak out past the checkvalve 16 and in such cases the check valve is held in tight sealingengagement with the end of the duct 14 by pressure in the duct 'I9communicated to the underside of the check valve.

The time period during which the downward movement of the plunger isdelayed, adjusted by the screw I8 as described determines the frequencyof successive operations or the delay which must occur before asucceeding operation can be effected, the adjustment of such timeperiods therefore being referred to as the frequency adjustment or thedelay-period adjustment.

The above described operation is for a single weld, the operatorscontactor |6 being only momentarily closed. If it is held closed, theapparatus after restoring as above described, will continuously repeat,maldng successive welds.

In Figs. 2 and 2A are illustrated a modification of my invention. Withthis form the cold-hold period is determined and adjusted as describedin the form of Fig. 1. In this form, however, when the current impulsehas been timed and the plunger has reached the top of its stroke andstarts the cold-hold period, a valve |34 is moved to an upper positionby the bar 52 on the plunger, in a manner similar to movement of thevalve 88 of Fig. 1. The valve has two necks thereon |35 and |36. Whenthe valve is in its normal lower position illustrated, the risingpressure in the cylinder is conducted by a conduit |31 to a duct |38 inthe block |39 which supports the valve |34 and in which it reciprocates.The duct |38 communicates with the space around the lower neck |36 ofthe valve, thence by a duct |40 and a duct |4| with a conduit |42connected to the valve housing |43 as shown in Fig. 2 and Fig. 2A.

The air thus supplied moves the valve 62 of Fig. 1A down and operatesthe plunger 20 as described for Figs. 1 and 1A. y

When the plunger reaches the top of its stroke, it moves the valve |34to its upper position, thereby effecting an exhaust from under thepiston 56, which, by referring to Fig. 2A, allows the air under pressureto flow past the check valve 16 through the duct 19 to the chamber 68into the space above the valve 62, which is now in its lower position,as will be understood, and out at the duct 60, by way of the conduit|42, through the duct |4| and through a duct |44, around the upper neckof the valve |34 which is now aligned with the duct |44, and out by wayof a duct to atmosphere. The pressure under the piston 56 yin the valvecylinder 55 above the valve 62 is sufficient to hold the valvedownwardly against the spring 63.

An adjusting valve screw |46 controls and adjusts the effective size ofthe duct |44 and controls the flow of air therethrough and thereforecontrols the rate at which the piston 56 descends, thereby adjustablycontrolling the said frequency or delay time period.

In some instances, particularly when the cold hold period is adjusted tobe relatively long, the exhaust of air past the needle valve |46 maypermit the plunger 20 to descend before the end ofthe cold hold period,and when the plunger has once descended and restored the valve |34, theplunger will be given air again and will again reciprocate upwardly,sending another unwanted impulse of current to the electrodes. Toprevent this, in some cases a second adjusting needlevalve |41. isprovided. With the valve |34 in its upper position, back pressure fluidin the conduit |31 is conducted by a duct |48 around the lower neck ofthe valve |34 (which is now in the upper position), past the needlevalve |41, communicating the pressure to the duct |4| and the conduit ,i

|42 and providing sufficient pressure under the piston 56 to prevent theplunger from returning, or to prevent it from returning too rapidly.

lAt the end of such long cold-hold periods, and after the valve has beenrestored, the pressure in the conduit dies out due to the exhaust of thecylinder 1 and thereupon the pressure supplied to the conduit I 42 isdiscontinued and the plunger can descend, or, if descending can at oncecomplete its stroke downwardly.

By this double adjustment, the reutrn of the plunger can be delayed aslong as desired, or if desired may be held at the top of its strokeuntil after the cold-hold period is ended.

With this arrangement, 'when the cold-hold periods are short, theadjusting screw |41 can be screwed all the way in to block the port |48,placing all of the adjustment on the screw |46.

My invention is not limited to the exact details illustrated anddescribed. Changes and modifications may be made within the spirit of myinvention Without sacrificing its advantages and within the scope of theappended claims.

I claim:

1. An electric contactor mechanism operable to close an electric circuitand then after a time interval to open it, a delayed operation contactordevice actuable by operation of the contactor mechanism to initiate therunning of a second time interval, and controlling a second electriccircuit at the end of the second time interval, and means for restoringthe device actuated by restoring of the contactor mechanism.

2. An electric contactor mechanism operable to close a rst electriccircuit and then after a rst time interval to open it, means including adelayed operation contactor device actuable by operation of thecontactor mechanism to initiate the running of a second time intervaland controlling a second electric circuit at the end of the second timeinterval, electrically actuable means controlled by the second electriccircuit, means controlling the device to cause its associated secondelectric circuit to effect actuation of the electrically actuable meansafter opening of the rst electric circuit by the electric contactormechanism, and means for restoring the device actuated by restoring ofthe contactor mechanism.

3. An electric contactor comprising a normally restored movable elementand comprising electric contacts operable by movement of the movableelement to close an electric circuit and then after a time interval toopen the circuit, a delayed operation contactor device actuable bymovement of the movable element to initiate the runing of a second timeinterval and controlling a second electric circuit at the end of thesecond time interval, means to retard restoring of the contactor movableelement to time the frequency of successive operations of the contactor,and means for restoring the device actuated by restoring of thecontactor movable element.

4. An electric contactor comprising a movable element, and comprisingelectric contacts operable by movement of the movable element to closeand then open an electric circuit, delayed operation means actuable bymovement of the movable element to initiate the running of a timeinterval, and arranged to control a second electric circuit at the endof the time interval, and means introducing a time interval betweensuccessive operations of the movable element to time the frequency ofsuccessive operations thereof.

5. An electric contactor comprising a movable element and comprisingcontacts operable upon movement of the movable element in one directionto close and then open an electric circuit, a delayed operationcontactor device'of the stored energy type actuable to release energytherefrom by movement of the movable element in said direction toinitiate the running of a time interval and arranged to control a secondelectric circuit at the end of the time interval, and means for storingenergy in the delayed operation device actuated by restoring movement ofthe contactor movable element in the other direction.

6. A pneumatically operable electric contactor comprising a fluidpressure chamber and a movable element reciprocable in one direction byiiuid pressure communicated to the chamber, and comprising electriccontacts arranged to be closed and then after a time interval, to beopened by movement of the reciprocal element in said direction, meansfor controlling communication of fluid pressure to the chamber foradjustably varying the velocity of said movement of the reciprocalelement to adjustably vary the time interval, a delayed operation deviceof the piston and cylinder stored energy type actuable by said movementof the reciprocal element to start the running of a second timeinterval, an adjustable valve controlling fluid pressure in the cylinderto control the duration of the second time interval, electric Contactmeans controlled by the device at the end of the second time interval,valve means controlling the communication of fluid pressure to thecontactor chamber to effect reciprocation of the reciprocable element,means controlling the velocity of said return reciprocation and means tostore energy in the delayed operation device operable by saidreturnreciprocation.

7. The apparatus described in claim 6 and in which the said valve meanscomprises a valve operated by reciprocation of the reciprocable elementin said one direction and restored by its return reciprocation.

8. In a pneumatically operable electric contactor construction, areciprocable element, a Iiuid pressure chamber arranged to be connectedto a source of fluid pressure and having a movable wall forreciprocating the movable element upon communication of uid pressure tothe chamber from the source, mechanism means comprising a cam and a camfollower, one movable with the reciprocable element, and electriccontactor means operated thereby to eiect the closing of an electriccircuit followed by opening thereof upon reciprocation of thereciprocable element in one direction and the mechanism means beingineffective to Operate the contactor means upon return reciprocation,conduit means communicating with the chamber, a valve controlling theconduit means and operated by movement of the reciprocable element insaid one direction to exhaust pressure from the chamber to eiect thereturn reciprocation of the movable element, means for adjusting therate of said exhaust to adjust the velocity of return reciprocation, anenergy storage device comprising a piston element and a cylinder elementone of which is movable, mechanical means for reciprocating the movableelement in one direction thereby tending to change the pressure in thecylinder, adg.

justable valve means controlling a passageway communicating with thecylinder and with the atmosphere to adjustably vary the rate of movementof said movable element, means to restore the movable element operatedby said return reciprocation of the reciprocable element, and auxiliaryswitch means operated by the movable element at the end of a timeinterval.

9. In a pnuematically operable electric contactor construction, areciprocable element, a fluid pressure chamber arranged to be connectedto a source of uid pressure and having a movable Wall for reciprocatingthe movable element upon communication of Huid pressure to the chamberfrom the source, mechanism means associated with the reciprocableelement and electric contactor means operated thereby to effect theclosing of an electric circuit followed by opening thereof uponreciprocation of the reciprocable element in one direction and themechanism means being ineiective to operate the contactor means uponreturn reciprocation, conduit means communicating with the chamber, avalve controlling the conduit means and operated by movement of thereciprocable element in said one direction to initiate exhaust ofpressure from the chamber to effect the return reciprocation of themovable element, and means for adjusting the reate of said exhaust toadjust the velocity of return reciprocation, independently of the valve.

10. In a pneumatically operable electric contactor construction, areciprocable element, a uid pressure chamber arranged to be connected toa source of fluid pressure and having a movable Wall for reciprocatingthe movable element upon communication of Iiuid pressure to the chamberfrom the source, mechanism means associated with the reciprocableelement and electric contactor means operated thereby to effect theclosing of an electric circuit followed by opening thereof uponreciprocation of the reciprocable element in one direction and themechanism means being ineiective to operate the contactor means uponreturn reciprocation, conduit means communicating with the chamber, avalve controlling the conduit means and operated by movement of thereciprocable element in said one direction to exhaust pressure from theChamber to effect the return reciprocation of the movable element, meansfor adjusting the rate of said exhaust to adjust the velocity of returnreciprocation, and a conduit arranged to be connected to a source ofIluid pressure and controlled by the valve upon said operation thereofto admit source pressure to the said conduit means, and adjustable valvemeans for adjusting the rate of said uid pressure admission.

CHARLES H. RIPPL.

